Abstract

A new method is developed to detect edges and their directional edge segments from real objects based on edge enhancement of a ferroelectric liquid-crystal spatial light modulator (FLC-SLM) and optical spatial filtering. Real image of an object is written onto a FLC-SLM through a camera lens and incoherent-coherent image conversion is performed. Edge enhancement can be performed on the same FLC-SLM, when the alignment direction is coincident with the direction of polarization of read-out light. Resultant image has bright (or dark) edges with thin width. Next, directional edge segments with any size and angle can be extracted using optical spatial filtering, which is realized by the other FLC-SLM. To confirm availability of this method, we constructed a prototype system. Resolution of the FLC-SLM we used is more than 30 1p/mm and available area is 15mm by 15mm square. Both FLC-SLMs can be operated by synchronized mode with 1kHz clock. Processing speed of the system is 30 to 200 times faster than that of an electric processing. Experimental results and system evaluation are presented.

© 1993 Optical Society of America